Medication Summary

Factor IX is the treatment of choice for acute hemorrhage or presumed acute hemorrhage. Recombinant factor IX is the preferred source for replacement therapy. The factor IX activity level should be corrected to 100% of normal for potentially serious hemorrhage (eg, CNS, trauma related, GI, GU, epistaxis) and to 30-50% of normal for minor hemorrhage (eg, hemarthrosis, oral mucosal, muscular).

One unit of factor IX is the amount of factor IX in 1 mL of plasma (1 U/mL or 1%). The volume of distribution of factor IX is approximately 100 mL/kg. To find the number of units of factor IX needed to correct the factor IX activity level, use the following:

The difference between the desired factor IX activity level and the patient's native factor IX activity level is expressed as a fraction. For example, if 100% activity is desired and the patient’s native activity is 5%, the calculation is as follows:

100% - 5% = 95% or 0.95

As an example, an 80-kg person with hemophilia with known 1% factor IX activity level presents to the emergency department with a serious upper GI bleed. The desired factor IX activity level is 100%. The dose of factor IX to administer to the patient would be calculated as follows:

Units factor IX = (80 kg)(100 mL/kg)(1 U factor IX/mL)(.99) = 7920

The next dose should be administered 24 hours after the first and is one half of the initial calculated dose.

Minor hemorrhage requires 1-3 doses of factor IX. Major hemorrhage requires many doses and continued factor IX activity monitoring with the goal of keeping the trough activity level at least 50%. Continuous infusions of factor IX may be considered for major hemorrhage.

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Factor IX-containing Products

Class Summary

These agents are used to correct the patient's native deficiency, with the goals of achieving a normal hematologic response to hemorrhage or preventing hemorrhage. Fresh frozen plasma is no longer used in hemophilia because of the lack of safe viral elimination and concerns regarding volume overload.

Recombinant factor IX (rFIX) uses no human products for stabilization. Each of the brands is FDA-approved for control and prevention of bleeding episodes, and for perioperative management in adults and children. Rixubis and Alprolix are also approved for routine prophylaxis in adults and children. Alprolix is a long-acting product, it may be administered for routine prophylaxis once weekly or every 10 days. Rebinyn is a glycopegylated long-acting rFIX. Pegylation slows removal of FIX from the blood circulation.

Recombinant protein that temporarily replaces missing coagulation Factor IX needed for effective hemostasis. Comprised of genetically fused recombinant coagulation Factor IX and recombinant albumin, which extends the half-life of Factor IX. It is indicated for on-demand control and prevention of bleeding episodes, management of postoperative bleeding, and as prophylaxis to reduce the frequency of bleeding episodes.

Coagulation Factor VIIa (Recombinant)

Class Summary

This agent is indicated to treat bleeding episodes in patients with hemophilia A or B and inhibitors. It promotes hemostasis by activating the extrinsic pathway of the coagulation cascade, forming complexes with tissue factor, and promoting activation of factor X to factor Xa, factor IX to factor IXa, and factor II to factor IIa.

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Antifibrinolytics

Class Summary

These agents are used in addition to factor IX replacement for oral mucosal hemorrhage and prophylaxis, as the oral mucosa is rich in native fibrinolytic activity. These agents are used in prophylaxis for oral surgery and in the treatment of excessive bleeding in the oral mucosa that results from local fibrinolytic activity. Their use is contraindicated as initial therapies for hemophilia-related hematuria originating from the upper urinary tract because they can cause obstructive uropathy or anuria. They should not be used in combination with prothrombin complex concentrate (PCC).

This is a lysine analog that binds to natively produced plasmin, reducing its fibrinolytic activity.

This agent inhibits fibrinolysis by inhibiting plasminogen activator substances and, to a lesser degree, antiplasmin activity. The principal drawbacks of this agent are that thrombi formed during treatment are not lysed, and its effectiveness is uncertain. It has been used to prevent recurrence of subarachnoid hemorrhage.

This agent is widely distributed. Its half-life is 1-2 hours. Peak effect occurs within 2 hours. Hepatic metabolism is minimal.

The main effect of desmopressin is enhancement of water reabsorption in the kidney and smooth muscle constriction. It causes a dose-dependent increase in plasma FVIII and plasminogen activator.

This agent increases the cellular permeability of collecting ducts, resulting in renal reabsorption of water. Tachyphylaxis may occur, even after first dose, but the drug can be effective again after several days.

This agent is a freeze-dried sterile human plasma fraction with factor VIII inhibitor bypassing activity. It contains factors II, IX, and X, mainly nonactivated; and factor VII, mainly in the activated form. It may shorten the activated partial thromboplastin time of plasma containing factor VIII inhibitors. Anti-inhibitor coagulant complex is indicated for prevention and control of spontaneous hemorrhage or bleeding during surgical interventions in hemophilia patients who have autoantibodies or alloantibodies to coagulation factors. It is also indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in patients with hemophilia A or B who have developed inhibitors.

FVIII is a protein in normal plasma that is necessary for clot formation and hemostasis. It activates factor X in conjunction with activated FIX; activated factor X converts prothrombin to thrombin, which converts fibrinogen to fibrin, which, with factor XIII, forms a stable clot.

FVIII is a protein in normal plasma that is necessary for clot formation and hemostasis. It activates factor X in conjunction with activated FIX; activated factor X converts prothrombin to thrombin, which converts fibrinogen to fibrin, which, with factor XIII, forms a stable clot.

This agent replaces deficient FIX and other factors in the complex. AlphaNine SD and Mononine contain only FIX. BeneFIX is a recombinant product.

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Monoclonal Antibodies

Class Summary

These agents are monoclonal antibodies directed against the CD20 antigen on B cells. They are recommended as second-line therapy in the treatment of factor IX inhibitors, especially in cases with high inhibitor titers.

Urasinski T, Stasyshyn O, Tatiana A, et al. Pharmacokinetics, Efficacy and safety of a recombinant Factor IX (BAX326) in previously-treated pediatric patients <12 years of age with severe or moderately severe hemophilia B. Presented at the 55th Annual Meeting of the American Society of Hematology (ASH) in New Orleans, LA; December 7-13, 2013.